The Bharatiya Janata Party (BJP) is a nationalist political party in India. It is the largest political party in India and the world's largest party in terms of primary membership. It is one of two major national parties in India, along with the Indian National Congress. It is the ruling party of the National Democratic Alliance, a coalition of several regional parties. The BJP has its roots in the Bharatiya Jana Sangh, a right-wing Hindu nationalist political party that was founded in 1951. After the State of Emergency in 1977, the Jana Sangh merged with several other parties to form the Janata Party, which defeated the incumbent Congress party in the 1977 general election. After three years in power, the Janata Party dissolved in 1980 with the members of the Jana Sangh reconvening to form the BJP.